On 29 October 1957 he suffered a broken arm after a 'Mills grenade' was thrown into the debating chamber of the Knesset. David Ben-Gurion and Golda Meir were also injured. The attack was carried out by Moshe Dwek, whose motives were attributed to a dispute with the Jewish Agency, though he was also described as 'mentally unbalanced'. He retained his seat in the 1959 and 1961 elections, and was reappointed Minister of Transportation towards the end of the fifth Knesset in 1965. When Ahdut HaAvoda merged with Mapai to form the Alignment, Carmel joined the new party and retained his ministerial post in the sixth Knesset.
Carmel remained a Knesset member until 1977, and published two books; Northern Campaigns (1949) and Between the Walls (1965). He died in 2003 at the age of 92.